1. Field of the Invention
The present invention relates to a static phase converter and more particularly a static phase converter which occupies a relatively small volume to enable it to be disposed within various appliances, such as refrigeration units, with minimal modification to reduce electrical power consumption.
2. Description of the Prior Art
Static phase converters are generally known in the art. Examples of such static phase converters are disclosed in U.S. Pat. Nos. 521,051; 852,027; 2,253,053; 2,253,392; 2,480,576; 2,832,925; and 2,968,757. Such static phase converters are generally used to convert a source single phase electrical power to multiple phase, such as three phase, electrical power in various applications. One such application is to use such static phase converters to reduce the power consumption of various appliances. such as refrigerators and the like. More specifically, known refrigeration units normally include a single phase compressor motor; for example, a one-half horsepower compressor motor. A one-half horsepower single phase motor will draw approximately 7.4 amperes at 120 volts AC. A three phase one-half horsepower motor will draw approximately 4.2 amperes at 120 volts--about 40% less current than a single phase motor with the same horsepower rating. By reducing the electrical current requirements of the compressor motor, the appliance, such as the refrigeration unit, is less expensive to operate. More specifically, the cost charged by an electric utility for operating an electrical appliance is in terms of kilowatt hours (KWH). The KWH is a product of the electrical voltage and the electrical current multiplied by the period of use. For a relatively constant voltage, reducing the electrical current requirement by approximately 40% will, in turn, reduce the KWH by approximately the same amount.
Such a reduction in the KWH can result in significant savings to consumers as well as considerable conservation of precious fossil fuel resources. For example, as mentioned above a refrigeration unit with a single phase one-half horsepower compressor motor draws 7.4 amperes at 120 volts or approximately 888 watts. Assuming a typical refrigeration unit would operate
approximately twelve hours per day, this yields 10.66 KWH per unit, per day per unit for operation. Multiplying this value by 365 days per year and by the approximately 72 million units in use in the United States today yields over 280 billion kilowatt hours per year for operation of the 72 million refrigeration units. If the single phase compressor motor in each of these refrigeration units was replaced with a three phase compressor motor having the same horsepower value, over 106 billion kilowatt hours would be saved per year, thus conserving precious fossil fuel resources as well as providing considerable savings to the consumers.
The problem with known static converters, such as those disclosed in the above-mentioned U.S. patents, is that they are relatively too large to be disposed within appliance and therefore are generally used infrequently with appliances and generally only in commercial applications. In such applications of the above-mentioned static phase converters, the units are mounted exterior to the appliance housing. In addition to requiring more space for the appliance, such an application results in increased cost to the consumer due to the interconnection wiring required between the appliance and the static phase converter on site. Moreover, exterior mounting of the static phase converter relative to the appliance is unsuitable in residential applications.